A large number of people, including those suffering from conditions such as diabetes use some form of infusion therapy, such as daily insulin infusions to maintain close control of their glucose levels. There are currently two principle modes of daily treatment for insulin infusion therapy. The first mode, referred to as Multiple Daily Injections or MDIs, includes syringes and insulin pens. These devices are simple to use and are relatively low in cost, but they require a needle stick at each injection, typically three to four times per day. The second mode includes infusion pump therapy, which entails the purchase of an insulin pump that lasts for about four years. The initial cost of the pump can be significant, but from a user perspective, the overwhelming majority of patients who have used pumps prefer to remain with pumps for the rest of their lives. This is because infusion pumps, although more complex than syringes and pens, offer the advantages of continuous infusion of insulin, precision dosing and programmable delivery schedules. This results in closer blood glucose control and an improved feeling of wellness.
However, patients may encounter situations wherein different configurations of infusion pumps, reservoirs and line sets are required for one or more reasons, and such patients may become concerned that the different configurations could adversely affect dosing and programmable delivery schedules. Plus, many current systems and methods require user actions or motions not fully compatible with each user's abilities.
For example, a first conventional system and method requires two separate engagement/disengagement operations for connecting the reservoir and line set to the infusion pump. For engagement, the user first slides or pushes a reservoir into the pump reservoir cavity, then turns a separate threaded sleeve with sufficient torque to thread and tighten the sleeve into position. For disengagement, the user first unscrews the separate threaded sleeve, and then pulls the reservoir from the pump reservoir cavity. The human factors are not intuitive with this second operation, and there is a tendency to unscrew the line connection from the reservoir. Applying a counter clockwise turning motion to the only grip point, i.e. the Luer connector, will unscrew the Luer, allowing insulin to leak onto the top surface of the reservoir and create an opportunity for the leaked insulin to migrate into the pump reservoir cavity as the reservoir is pulled from the cavity. Also, at least one or more sealing O-rings are typically provided in such devices, and the compression forces required by such O-rings can be substantial. Still further, once released in a manner described above, there are few grip points from which to pull the released reservoir from the pump reservoir cavity.
Another failure that could occur in such a system and method is the separation of the line from the Luer connector, again resulting in insulin leakage from the line. Also, in many such systems and methods, there is no audible feedback when the separate threaded sleeve has been torqued to the proper degree, nor is there any visible indication that the separate threaded sleeve has disengaged, i.e. unscrewed to some degree, during use.
In such a system and method, the user motions necessary to place the reservoir into the pump reservoir cavity and complete the engagement of the line set connection are excessive and not intuitive, and the separate threaded sleeve is akin to a wear component requiring periodic replacement. However, the user may not always know when the sleeve requires replacement and failure to replace the sleeve could result in contamination from the worn elastomer migrating into the pump reservoir cavity or loss of ability to properly engage and torque the separate threaded sleeve. Still further, the separate threaded sleeve could also be lost or misplaced, since it is not an integral part of either the reservoir, line set or pump.
In yet other systems and methods, the O-ring used to seal the space between the reservoir, connector and the pump reservoir cavity can be located within the pump reservoir cavity, and needs to be replaced periodically by the user for proper operation. However, removal of the O-ring can be difficult for some users with limited dexterity, and improper removal of the O-ring can result in O-ring contamination migrating into the pump reservoir cavity or depending on the O-ring removal tool, can result in damage to the O-ring groove which retains the O-ring in the pump reservoir cavity. Ultimately, this damage can impact dosing or pump performance. Further, O-ring wear can occur which may not be noticeable to the user, causing O-ring particulates to enter the pump reservoir cavity or loss of sealing capabilities of the O-ring and migration of contaminates into the pump reservoir cavity.
Still further, the connection features and procedures that are used in such conventional infusion pumps include one or more of two-start threads, detent grooves, and a single thread. Accordingly, such systems require a certain degree of phase alignment for connecting the reservoir to the infusion pump. For example, being “in phase” means that the rotational (angular) or Cartesian (x, y) relationship between the features is the same on every pump, i.e. the threads start at the same angular increment from a detent groove on every pump. Accordingly, many components of such systems cannot be interchanged.
Accordingly, a need exists for a system and method of infusion pump management having improved human factors for reservoir and pump connection, and providing a reservoir and connector that can be easily engaged with all of the currently marketed infusion pumps.